Hello
First off, the number before the . is 4, that is the biggest number
The number closest to the left is the biggest
4.56 and 4.5 are bigger than 4.48
So you can eliminate 4.48 straight away
4.6 is bigger than 4.56 and 4.5, so you can get rid of those as well.
The tree which is 4.6 meters tall is the tallest
Hope this helps
-GoldenWolfX